Pardon the CoffeeScript.
In your code:
App.BootstrapInitComponent = Ember.Component.extend
initTabs : (()->
$('.nav-tabs .active').tab('show')
).on 'didInsertElement'
In your template:
<ul class="nav nav-tabs">
<li><a class="active" data-toggle="tab" href="#transactions">Transactions</a></li>
<li><a data-toggle="tab" href="#vouchers">Vouchers</a></li>
</ul>
{{bootstrap-init}}
That's it. The tab with class="active" will be visible upon view load. I haven't tried it yet, but the same method should work fine with others Bootstrap elements that need initialization too (popovers, dropdowns, whatnot). Just add code to initTabs.